What types of Pulmonary Hypertension are seen in Systemic Sclerosis?
Patients with SSc most often have PAH (Group 1), but can also have other types, particularly Pulmonary Hypertension due to left heart disease (Group 2) or PH-ILD (Group 3).
Because PAH-specific therapies are currently only approved for patients with PAH (Group 1), distinguishing whether a patient has PAH or an alternative category is very important.
A diagnosis of PAH absolutely requires cardiac hemodynamic assessment via RHC and is defined by a mean pulmonary artery pressure >25 mmHg, pulmonary capillary wedge pressure (PCWP) of <15 mmHg, and pulmonary vascular resistance of >3 Wood units.
In Pulmonary Hypertension due to left heart disease, the elevated pulmonary pressures are a result of either systolic or diastolic dysfunction and confirmed by an increased PCWP >15mmHg on RHC. With Pulmonary Hypertension-ILD, the elevated pulmonary pressures are considered to be a result of chronic hypoxia secondary to underlying lung disease. It is often a challenge to determine the degree of ILD necessary to cause secondary Pulmonary Hypertension.
